ES2432433T3 - Polyurethane prepolymers - Google Patents

Abstract

Polymers modified with alkoxysilane groups free of liquid isocyanate groups at room temperature (23 ° C) with an average numerical molecular weight of less than 5,000 g / mol that can be obtained by reacting a) an isocyanate-reactive hydrogen-containing prepolymer containing structural units of the general formula (I), in which PIC represents a residue of a reduced polyisocyanate (B) in the isocyanate groups, Y1 represents nitrogen, oxygen or sulfur, R1 represents either a pair of free electrons or hydrogen or represents a discretionary organic moiety, To a reduced moiety in the isocyanate reactive groups of an isocyanate reactive polymer and low molecular weight multifunctional isocyanate reactive compounds, which is comprised of multifunctional low molecular weight isocyanate reactive compounds (A1) and discrete polyether polyols (A2), or either in the form of blocks, alternating or statistical, linked together by elele Structural formula of the formula -Y2-C (C> = O) -NH-PIC-NH- (C> = O) -Y1 (R1) - in which Y1 and Y2 independently represent nitrogen, oxygen or sulfur, which comes from the polyisocyanates B, being able to treat the terminal groups of these substructures, totally or partially, also of the corresponding thiocomposites or amine derivatives, being 1 to 40% by weight of substructures A1 of an average molecular weight (Mn) of less than 500 g / mol and from 60 to 99% by weight of A2 substructures of an average molecular weight (Mn) of more than 500 g / mol, and A having a total functionality of 2 to 6 in total, conb) an isocyanatofunctional alkoxysilane compound (component C) of the general formula (II) in which Z1, Z2 and Z3 are the same or different C1-C8 alkoxy or C1-C8 alkyl moieties, which may also be bridged, at least one residue must be present in each atom of Si C1-C8 alkoxy, Q is a linear or branched difunctional organic moiety, preferably an alkylene radical with 1 a8 carbon atoms.

Description

Polyurethane prepolymers

The present invention relates to polyurethane prepolymers, a process for its preparation and its use as binders for adhesives, coatings or foams.

Alkoxysilanofunctional polyurethanes that are crosslinked by polycondensation of silanes have long been known. A compilation article related to this theme is found, for example, in “Adhesives Age” 4/1995, page 30 et seq. (authors: Ta-Min Feng, B. A. Waldmann). Such one component polyurethanes terminated in alkoxysilane that harden with moisture are increasingly used as masses of coating, sealing and flexible adhesives in the construction industry and the automotive industry.

Such alkoxysilanofunctional polyurethanes can be prepared according to US-A 3,627,722 or DE-A 1 745 526 by reacting eg polyethers with an excess of polyisocyanate to obtain a prepolymer containing NCO, which is then reacted again with an alkoxylan aminofunctional.

Publications EP-A 0 397 036, DE-A 19 908 562 (corresponding to EP-A 1 093 482) and US-A 2002/0100550 describe other different ways of preparing alkoxysilane-terminated polymers. According to these publications, high molecular weight polyethers with an average molecular weight of 4,000 g / mol or greater are used respectively,

EP-A 0 070 475 describes the preparation and use of alkoxysilane terminated polymers starting from prepolymers with acidic hydrogen by termination with NCO-functional alkoxysilanes. For the synthesis of the prepolymer polyols with a molecular weight of 500-6,000 g / mol are used. The polymers described therein are used as binders in sealant formulations, that is flexible systems.

An analogous procedure described is described in the application DE-A 10 2007 058 344.

All these alkoxysilane-terminated systems form flexible polymers after hardening with relatively small strength and high breakage elongation. DE-A 1 745 526 describes tensile strengths in the range of 3.36 kg / cm 2 to 28.7 kg / cm 2 for polyoxypropylene glycol based polymers. Only with crystallizing polycaprolactones are high strengths achieved that are sufficient for structural adhesions.

However, these systems are very viscous or solid at room temperature and therefore can only be hot worked.

Correspondingly, the scope of the aforementioned applications is limited on the one hand to flexible sealants and adhesives, on the other hand to very viscous or solid systems that can only be hot worked. The present invention is therefore based on the objective of providing liquid alkoxysilane terminated polyurethanes at room temperature that hardened reach a high cohesion resistance, so that adhesives that make structural adhesions possible can be formulated therewith.

It has now been found that such alkoxysilane terminated polyurethanes can be prepared by first preparing an isocyanate-reactive hydrogen-containing prepolymer from a polyisocyanate and a mixture of compounds with isocyanate-reactive groups. In this regard, in the mixture of compounds with isocyanate reactive groups, multifunctional isocyanate reactive compounds of low molecular weight with a molecular weight <500 g / mol in 1 to 40% by weight are present. The prepolymer having hydrogen reactive with isocyanate obtained is finally modified with an isocyanatofunctional alkoxysilane.

Accordingly, objects of the invention are polymers modified with alkoxysilane groups which can be obtained by reaction of

a) an isocyanate reactive hydrogen containing prepolymer containing structural units of the general formula (I),

in which

PIC represents a residue of a reduced polyisocyanate (B) in the isocyanate groups, 2

Y1 represents nitrogen, oxygen or sulfur,

R1 represents either a pair of free electrons or hydrogen or represents a discretionary organic moiety,

To a reduced moiety in the isocyanate reactive groups of an isocyanate reactive polymer and low molecular weight multifunctional isocyanate reactive compounds, which is composed of multifunctional low molecular weight isocyanate reactive compounds (A1) and polyether (A2) in sequence discretionary, that is in the form of blocks, alternating or statistical, linked together by the structural element of the formula

-

Y2-C (C = O) -NH-PIC-NH- (C = O) -Y1 (R1)

in which Y1 and Y2 independently represent each other nitrogen, oxygen or sulfur, which comes from

polyisocyanates B, being able to treat the terminal groups of these substructures, totally or partially,

also of the corresponding thiocomposites or amine derivatives, being

1 to 40% by weight of A1 substructures of an average molecular weight (Mn) of less than 500 g / mol and

60 to 99% by weight of A2 substructures of an average molecular weight (Mn) of more than 500 g / mol,

and presenting A in total an average functionality of 2-6,

with

b) an isocyanatofunctional alkoxysilane compound (component C) of the general formula (II):

in which

Z1, Z2 and Z3

they are the same or different C1-C8 alkoxy or C1-C8 alkyl moieties, which may also be bridged,

at least one C1-C8 alkoxy moiety must be present in each atom of Si,

Q

it is a linear or branched difunctional organic moiety, preferably an alkylene radical with 1 to

8 carbon atoms

In this regard the reaction of b) with a) can be carried out in a ratio of 0.8: 1.5 to 1.5: 1.0 (NCO: Y-H).

The compounds according to the invention are non-crystallizing substances, liquid at room temperature with an average numerical molecular weight of less than 5,000 g / mol, preferably less than 4,000 g / mol and a viscosity of less than 700 Pas at 23 ° C, preferably less than 500 Pas at 23 ° C.

The mixture of isocyanate reactive compounds (component A) consists of 1-40% of a low molecular weight multifunctional isocyanate reactive compound (A1) with 2-6 isocyanate reactive groups and an average numerical molecular weight of less than 500 g / mol and 60 -99% of an isocyanate reactive compound (A2) with 2-6 isocyanate reactive groups and an average numerical molecular weight of more than 500 g / mol, both A1 and A2 may be constituted respectively by combinations of compounds with isocyanate reactive groups, as long as these compounds are within the limits described above in relation to molecular weight.

As component A, all compounds with isocyanate reactive groups known to those skilled in the art having an average functionality of at least 2 can be used. These can be for A1, for example, multifunctional low molecular weight isocyanate reactive compounds such as polyols or polyamines aliphatic, polyols or aromatic polyamines and for A2, for example, isocyanate reactive compounds of higher molecular weight such as polyether polyols as well as polyol thioethers. Preferably such isocyanate-reactive compounds have an average functionality of 2 to 6, preferably 2 to 3.5 and especially preferably 2 to 3.

Preferably in component A1 polyhydroxy alcohols, preferably dihydroxy or trihydroxy alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3- / 1,4-butanediol, 1,3 / 1,6-hexanediol are used , 1,8-octanediol, neopentyl glycol, 1,4-bis (hydroxymethyl) cyclohexane, bis (hydroxymethyl) tricyclo [5.2.1.02.6] decane or 1,4-bis (hydroxymethyl) benzene, 2-methyl-1,3 -propanediol, 2,2,4-trimethylpentane-1,3-diol, 2-ethyl-1,3-hexanediol, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, 1,4-phenol dimethanol, bisphenol A, tetrabromobisphenol A, glycerin, trimethylolpropane , 1,2,6hexanotriol, 1,2,4-butanotriol, pentaerythrite, quinite, mannite, sorbitol, methylglucoside and 4,3,6-dianhydrohexite.

Suitable aliphatic amines may be di- or triamines, eg ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butanediamine, neopentanediamine, 1,5-diamino-2-methylpentane (Dytek® A, DuPont) , 2-butyl2-ethyl-1,5-pentanediamine, 1,6-hexamethylenediamine, 2,5-diamino-2,5-dimethylhexane, 2,2,4-and / or 2,44-trimethyl-1,6-diaminohexane, 1,8-diaminooctane, 1,11-diaminoundecane, 1,12-diaminododecane, 4-aminomethyl-1,8octanediamine (triaminononane), diethylenetriamine, triethylenetetramine, cycloaliphatic amines such as, for example, 1-amino3,3,5-trimethyl- 5-aminomethyl-cyclohexane (isophorondiamine, IPDA), TCD-diamine, 1,4-cyclohexanediamine, 2,4-and / or 2,6-hexahydrotoluylenediamine (H6TDA), isopropyl-2,4-diaminocyclohexane and / or isopropyl-2 , 6-diaminocyclohexane, tricyclodecanobis (methylamine), 1,3-bis- (aminomethyl) -cyclohexane, 2,4'-and / or 4,4'-diaminodicycloheoxymethane (PACM 20), 3,3'-dimethyl-4, 4'-diamino-dicyclohexylmethane (Laromin® C 260, BASF AG, DE), the isomers, diaminodicyclohexylmethanes they have such a methyl substituent group in the core (such as C-monomethyldiaminodicyclohexylmethanes), 3 (4) -aminomethyl-1-methyl-cyclohexylamine (AMCA) as well as araliphatic di-o triamines, such as 1.3 -diaminobenzene, 1,4-diaminebenzene, 2,4-y / or 2,6-diamineotoluene (TDA), 1,3-bis- (aminaomethyl) benzene, 3,5-diethyl toluene-2,4-diamine, m- xylylenediamine, 4,6-dimethyl-1,3-benzenedimethanoamine, 4,4'-y / or 2,4'-y / or 2,2'-methylenebisbenzeneamine (MDA), or amines containing heteroatoms, diamine dimers of fatty acids, bis- (3-aminopropyl) -methylamine, 4,9-dioxadodecane-1,12-diamine or 4,7,10-trioxatridecane-1,13-diamine.

As component A2 polyethers are used. These are known in a known manner by alkoxylation of suitable starter molecules under basic catalysis or using bimetallic cyanide compounds (DMC compounds). Suitable starter molecules for the preparation of polyether molecules are with at least two element-hydrogen bonds reactive against epoxides or discretionary mixtures of such molecules.

Especially suitable polyethers are those of the type indicated above with a content of unsaturated terminal groups of less than or equal to 0.02 milliequivalents per gram of polyol (meq / g), preferably less than or equal to 0.015 meq / g, especially less preferably of or equal to 0.01 meq / g (ASTM D2849-69 determination method).

This is described, for example, in US-A 5 158 922 (eg example 30) and EP-A 0 654 302 (p. 5, line 26 to p. 6, line 32).

Suitable starter molecules for the preparation of polyol esters are, for example, simple low molecular weight polyols, water, ethylene glycol, propanediol-1,2, 2,2-bis (4-hydroxy-phenyl) propane, propylene glycol-1,3-and butanediol1 , 4, hexanediol-1,6, neopentyl glycol, 2-ethylhexanediol-1,3, trimethylolpropane, glycerin, pentaerythrite, sorbitol, organic polyamines with at least two NH bonds such as triethanolamine, ammonia, methylamine or ethylenediamine or discretionary mixtures of such initiator molecules. Suitable for alkoxylation are suitable alkylene oxides, especially ethylene oxide and / or propylene oxide, which can be used in discretionary sequence or also in admixture in alkoxylation.

Mixtures of polyethers containing at least one polyol with at least one tertiary amino group can also be used. Such polyethers having tertiary amino groups can be prepared by alkoxylation of starter molecules or mixtures of starter molecules that contain at least one starter molecule with at least 2 epoxy reactive element-hydrogen bonds, of which at least one is an NH bond, or low molecular weight polyol compounds bearing tertiary amino groups. Examples of suitable starter molecules are ammonia, methylamine, ethylamine, n-propylamine, iso-propylamine, ethanolamine, diethanolamine, triethanolamine, ethylenediamine, ethylenetriamine, triethanolamine, N-methyl-diethanolamine, ethylenediamine, N, N'-dimethylenediamine, tetra , hexamethylene diamine, 2,4-toulylenediamine, 2,6-toulylenediamine, aniline, diphenylmethane-2,2'-diamine, diphenylmethane-2,4'-diamine, diphenylmethane-4,4'-diamine 1-amino-methyl-3 -amino1,5,5-trimethylcyclohexane (isophorondiamine) didcyclohexylmethane-4,4'-diamine, xylylenediamine and polyoxyalkyleneamines.

Polyethers with organic fillers dispersed therein can also be used, such as addition products of toluylenediisocyanate with hydrazine hydrate or copolymers of styrene and acrylonitrile.

Polytetramethylene ether glycols with molecular weights of 400 g / mol to 4,000 g / mol which can be obtained by polymerization of tetrahydrofuran, but also polybutadienes containing hydroxyl groups can also be used.

Partially in component A, polyethermines can also be used in addition to the polyhydroxy compounds. With respect to the preferred molecular weights and composition of the mixture, the same limits already enumerated for the polyethers are valid.

The isocyanate-reactive compounds mentioned above can be reacted with all aromatic as well as aliphatic polyisocyanates before the prepolymerization itself which gives hydroxylic compounds.

modified with urethane.

As component B, aromatic, aliphatic and cycloaliphatic diisocyanates are considered as well as mixtures thereof. Suitable diisocyanates are compounds of the formula PIC (NCO) 2 with an average molecular weight of less than 400 g / mol, wherein PIC means an aromatic C6-C15 hydrocarbon residue, an aliphatic C4-C12 hydrocarbon residue or a residue of C6-C15 cycloalophatic hydrocarbon, for example diisocyanates of the butanediisocyanate series, pentanediisocyanate, hexanediisocyanate (hexamethylenediisocyanate, HDI), 4-isocyanatomethyl-1,8-octanediisocyanate (triisocyanathenocyanatohene, TIN), cyclohelenatene-cyanohenate, TIN , 5-trimethyl-1-isocyanate-3-isocyanatomethylcyclohexane (isophorondiisocyanate, IPDI), 2,4-and / or 2,6-methylcyclohexyldiisocyanate (H6TDI) as well as! ∀! '- diisocyanate-1,3-dimethylcyclohexane (H6XDI), xyl diisocyanate (XDI), 4,4'-diisocyanatodicyclohexylmethane, tetramethylene diisocyanate, 2-methyl-pentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate (THDI), dodecanemethylene diisocyanate, 1,4-diisocyanoccyclohexane, 4,4'-3,3-diisocyanate dimethyl-dicyclohexylmethane, 4,4'-diisocyanatodicyclohexylpropane, - (2,2), 3-isocyanatomethyl-1-methyl-1-isocyanoccyclohexane (MCI), 1,3-diisooctylcyanate-4-methyl-cyclohexane, 1,3-diisocyanate-2-methyl-cyclohexane and # ∀ # ∀ # '∀ #' - tetramethyl-mo -p-xylethylene diisocyanate (TMXD1), 2,4- / 2,6-toluenediisocyanate (TDI), methylenediphenylenediisocyanate (MDI), naphthyldiisocyanate (NDI). Preferably, IPDI, HDI or TDI or derivatives of MDI are used here.

The aforementioned aliphatic, cycloaliphatic or heterocyclic organic polyisocyanates may also be wholly or partially in the form of their derivatives, such as, for example, urethanes, biurets, allophanates, uretdiones, isocyanurates and trimerized and mixed forms of these derivatizations.

Basically, mixtures of several polyisocyanates can also be used, however, the use of only one polyisocyanate is preferred.

Isocyanatofunctional alkoxysilane compounds of the general formula (II) (component C) are basically suitable all monoisocyanates containing alkoxysilane groups with a molecular weight of 140 g / mol to 500 g / mol. Examples of such -metildietoxisilano 3-isocyanatopropyl methyldimethoxysilane isocianatometiltrimetoxisilano compounds isocianatometiltrietoxisilano, (isocyanatomethyl), (isocyanatomethyl), 3isocianatopropilmetil-dimethoxysilane, 3-isocyanatopropyltriethoxysilane and 3-isocianatopropilmetildietoxisilano. The use of 3-isocyanatopropyltrimethoxysilane is preferred here.

It is also possible according to the invention to use isocyanatofunctional silanes that have been prepared by reacting a diisocyanate with an amino-or thiosilane, such as those described in US 4,146,585.

or EP-A 1 136 495.

In addition, a process for the preparation of polymers modified with alkoxysilane groups according to the above description in which a mixture of isocyanate reactive compounds (component A) is first reacted with a polyisocyanate (component B) is obtained in order to obtain an isocyanate reactive hydrogen prepolymer, which is then capped by reaction with an isocyanatofunctional alkoxysilane (component C).

For the synthesis of an isocyanate-reactive hydrogen prepolymer, an excess of component A is used, namely, an NCO: Y1-H ratio of 1.0: 1.3 to 1.0: 3.0, especially preferably from 1.0: 1.5 to 1.0: 2.0.

This urethane can be accelerated by catalysis. For the acceleration of the NCO-OH reaction, urethane catalysts known per se to the person skilled in the art, such as organotin compounds or amine catalysts, are considered. Examples of organotin compounds include: dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin bis-acetoacetonate and tin carboxylates such as tin octoate. The indicated tin catalysts can be used if necessary in combination with amine catalysts such as aminosilanes or 1,4-diazabicyclo [2.2.2] octane.

Particularly preferably, dibutyltin dilaurate is used as a urethane catalyst.

In the process according to the invention this catalyst component is used, if co-used, in amounts of 0.001% by weight to 5.0% by weight, preferably from 0.001% by weight to 0.1% by weight and with special preference of 0.005% by weight to 0.05% by weight, based on the solids content of the process product.

The urethaneization of components A and B is carried out at temperatures of 20 ° C to 200 ° C, preferably from 40 ° C to 140 ° C and especially preferably from 60 ° C to 120 ° C.

The reaction is continued until a complete reaction of the isocyanate reactive groups is achieved. The course of the reaction is conveniently monitored by checking the NCO content and is finished when the corresponding theoretical NCO content is reached and remains constant. This can be done by suitable measuring devices installed in the reaction vessel and / or by analysis of samples taken. Suitable procedures are known to the person skilled in the art. These are, for example, viscosity measurements, NCO content measurements, refractive index, OH content, gas chromatography (GC), nuclear magnetic resonance spectroscopy ( NMR), infrared spectroscopy (IR) and near infrared spectroscopy (NIR). Preferably the NCO content of the mixture is determined by titration.

It is of little importance that the process according to the invention be carried out continuously, eg in a static mixer, extruder or kneader, or discontinuous, eg in a stirred reactor.

Preferably the process according to the invention is carried out in a stirred reactor.

The subsequent reaction of the prepolymers with isocyanate reactive hydrogen with isocyanatofunctional alkoxysilanes (component C) is carried out as described in EP-B 1 924 621 in a temperature range of 20 ° C to 200 ° C, preferably 40 ° C to 120 ºC and with special preference from 60 ºC to 100 ºC, quantitative ratios being selected as a rule using an excess of NCO groups, which in the end can be captured with isocyanate reactive compounds or allophanate.

Other objects of the invention are adhesives, coatings or foams based on the polyurethane prepolymers according to the invention. These adhesives, coatings or foams are crosslinked under the action of moisture by means of a polycondensation of silanols. The use of prepolymers according to the invention is preferred.

in adhesives, preferably in adhesives that have a tensile and shear resistance according to DIN EN 14293 of at least 5 N / mm2.

For the preparation of such adhesives, coatings and foams, polyurethane prepolymers having alkoxysilane end groups according to the invention can be formulated by known procedures together with plasticizers, fillers, pigments, drying agents, additives, photoprotectors, antioxidants, thixotropy agents, catalysts, binders and, if necessary, other common adjuvants and additives.

Typical adhesive and coating preparations according to the invention contain, for example, from 10% by weight to 100% by weight of a polymer modified with alkoxysilane groups according to one of claims 1 to 4 or a mixture of two or more such polymers modified with alkoxysilane groups, up to 30% by weight of a plasticizer or a mixture of two or more plasticizers, up to 30% by weight of a solvent or a mixture of two or more solvents, up to 5% by weight of a stabilizer of the moisture or a mixture of two or more moisture stabilizers, up to 5% by weight of a UV stabilizer or a mixture of two or more UV stabilizers, up to 5% by weight of a catalyst or of a mixture of two or more catalysts and up to 80% by weight of a charge or a mixture of two or more charges.

As suitable fillers are, for example, carbon black, silicic precipitation acids, pyrogenic silicic acids, mineral cretes and precipitation cretes. Suitable plasticizers include, for example, esters of phthalic acid, esters of adipic acid, esters of alkylsulfonic acid of phenol, esters of phosphoric acid or also high molecular weight polypropylene glycols.

As thixotropy agents are, for example, pyrogenic silicic acids, polyamides, sequential products of hydrogenated castor oil or polyvinyl chloride.

As suitable catalysts for hardening, all organometallic compounds and amine catalysts that significantly favor polycondensation of silanes can be used. They are especially suitable organometallic compounds, especially tin and titanium compounds. Preferred tin compounds are, for example: dibutyltin diacetate, dibutyltin dilaurate, dioctyltin maleate and tin carboxylates such as tin (II) octoate or dibutyltin bis-acetoacetonate. The indicated tin catalysts may be used in combination with amine catalysts such as aminosilanes or 1,4-diazabicyclo [2.2.2] octane. Preferred titanium compounds are, for example, alkyl titanates, such as ethyl diisobutyl bisacetoacetate titanate. For the general use of amine catalysts, those with a particularly high basic strength, such as amine with amidine structure, are suitable. Amine catalysts are therefore preferred, for example, 1,8-diazabicyclo [5.4.0] undec-7-ene or 1,5-diazabicyclo [4.3.0] non-5-ene.

As drying agents, especially alkoxysilyl compounds such as vinyltrimethoxysilane,

methyltrimethoxysilane, i-butyltrimethoxysilane, hexadecyltrimethoxysilane.

Functional silanes known as, for example, aminosilanes of the type indicated above but also N-aminoethyl-3-aminopropyl trimethoxy and / or N-aminoethyl-3-aminopropyl methyl dimethoxysilane, epoxysilanes and / or mercaptosilanes are used as binders.

Examples

The following examples illustrate the present invention without limiting it.

All percentage data refer, as long as nothing else is indicated, to weight percentage.

The determination of the NCO contents in% was carried out by back titration with 0.1 mol / l hydrochloric acid after reaction with butylamine, the basis of DIN EN 11909.

Viscosity measurements were carried out according to ISO / DIS 3219: 1990 at a constant temperature of 23 ºC and a constant cutting speed of 250 / s with a cone-plate rotation viscosimeter of Physica MCR type (Antón signature Paar Germany GmbH, Ostfildern, DE) using the CP 25-1 measuring cone (25 mm diameter, 1st cone angle).

The ambient temperature of 23 ° C that reigns during the time of the test is designated as TA.

Example 1 (according to the invention)

A mixture of 1,428.3 g of polypropylene glycol with a hydroxyl number of 28 mg of KOH / g and 198.4 g of tripolipropylene glycol was heated in a 5 l flask with lid, stirrer, thermometer and nitrogen flow hydroxyl number of 585 mg of KOH / g at 120 ° C. Then 141.4 g of hexamethylene diisocyanate (Desmodur® H, Bayer Material Science AG) were added and prepolymerized until no NCO content was detected by titration. Thereafter, 231.9 g of 3-isocyanopropyltrimethoxysilane were added at 120 ° C and stirred until the theoretical NCO content of 0.05% was reached. The excess NCO was captured by the addition of methanol. The polyurethane prepolymer having alkoxysilane end groups obtained had a viscosity of 98,100 mPas (23 ° C) and an average numerical molecular weight of 3,500 g / mol.

Comparative Example 1

A mixture of 1,758.8 g of polypropylene glycol with a hydroxyl number of 56 mg of KOH / g at 120 ° C was heated in a 1L multi-flask flask with a lid, stirrer, thermometer and nitrogen flow. Then 87.0 g of hexamethylene diisocyanate (Desmodur® H, Bayer Material Science AG) were added and prepolymerized until no NCO content was detected by titration. Subsequently, 154.2 g of 3-isocyanopropyltrimethoxysilane were added at 120 ° C and stirred until the theoretical NCO content of 0.05% was reached. The excess NCO was captured by the addition of methanol. The polyurethane prepolymer having alkoxysilane end groups obtained had a viscosity of 56,500 mPas (23 ° C) and an average numerical molecular weight of 3,100 g / mol.

Determination of skin formation time

Using a scraper (200 ∃m) a film is applied on a glass plate cleaned with ethyl acetate and immediately inserted into the dryness recorder ("Drying Recorder"). The needle is loaded with 10 g and moves for a time of 24 hours along a path of 35 cm.

The drying logger is in a room heated to 23 ° C and 50% relative humidity.

The time of disappearance of the permanent trace of the needle on the film is indicated as the skin formation time.

Examples of technical applications

For the evaluation of the technical application properties of the different polymers, these were processed in the following formulation:

Amount of use in% by weight

Polymer

46.06

Load (Socal® U1S2)

49.75

Drying (Dynasylan® VTMO)

2.76

Binder (Dynasylan® 1146)

1.38

Catalyst (Lupragen® N700)

0.05

For the preparation of the formulation, the polymer with the filler (Socal® U1S2; signature Solvay GmbH) and the secant (Dynasylan® VTMO; signature Evonik AG, Germany) are added as a binder and mixed in a vacuum solvent with wall scraper at 3,000 rpm. Then the binder (Dynasylan® 1146; signature Evonik AG) is added and

5 stir more gently at 1,000 rpm for 5 min. Finally, the catalyst is mixed by stirring at 1,000 rpm (Lupragen® N700; signature BASF SE, Germany) and finally the finished mixture is deaerated in vacuo.

For the measurement of the physical properties, both 2 mm thick membranes and samples for the determination of tensile shear strength are prepared. For the measurement of tensile shear strength, oak specimens are used for 7 days at 23 ° C / 50% humidity.

10 relative to the air, then 20 days at 40 ° C and then 1 day at 23 ° C / 50% relative humidity.

The hardness of the films is measured according to DIN 53505 and the tensile shear strength according to DIN EN 14293.

The following Table shows the results obtained:

Comp. one

Ex. 1

Shore D hardness

26 37

Tensile shear strength

3.1 7.3

Skin formation time [min]

60 fifty

Claims (7)

1. Polymers modified with alkoxysilane groups free of liquid isocyanate groups at room temperature (23 ° C) with an average numerical molecular weight of less than 5,000 g / mol which can be obtained by reaction of a) an isocyanate reactive hydrogen containing prepolymer containing structural units of the general formula (I), in which PIC represents a residue of a reduced polyisocyanate (B) in the isocyanate groups, Y1 represents nitrogen, oxygen or sulfur, R1 represents either a pair of free electrons or hydrogen or represents a discretionary organic moiety, A reduced moiety in the reactive groups with isocyanate of a polymer reactive with isocyanate and low molecular weight multifunctional isocyanate reactive compounds, consisting of 15 multifunctional isocyanate reactive compounds of low molecular weight (A1) and polyether polyols (A2) in discretionary sequence, that is in the form of blocks, alternating or statistical, linked together by the structural element of the formula

-

Y2-C (C = O) -NH-PIC-NH- (C = O) -Y1 (R1)

in which Y1 and Y2 independently represent each other nitrogen, oxygen or sulfur, which comes from 20 polyisocyanates B, being able to treat the terminal groups of these substructures, totally or partially, also of the corresponding thiocomposites or amine derivatives, being 1 to 40% by weight of substructures A1 of an average molecular weight (Mn) of less than 500 g / mol and 60 to 99% by weight of A2 substructures of an average molecular weight (Mn) of more than 500 g / mol, and A having a total functionality of 2 to 6, in total, 25 with b) an isocyanatofunctional alkoxysilane compound (component C) of the general formula (II) 30 in which Z1, Z2 and Z3 are the same or different C1-C8 alkoxy or C1-C8 alkyl moieties, which may also be bridged, and at least one C1-C8 alkoxy moiety must be present in each Si atom, Q is a linear or branched difunctional organic moiety, preferably an alkylene radical having 1 to 8 carbon atoms.

2. Compounds according to claim 1, characterized in that in the case of the polyether polyols (A2) it is polytetrahydrofuran polyols.

3.

 Compounds according to claim 1 with an average numerical molecular weight of less than 4,000 g / mol.

Four.

 Compounds according to claim 1 with a viscosity of less than 700 Pas at 23 ° C, preferably less than 500 Pas at 23 ° C.

Method for the preparation of polymers modified with alkoxysilane groups according to claims 1 to 4, characterized in that first a mixture of reactive compounds is reacted with isocyanate A (according to the definition of A with isocyanate reactive groups present) with a defective polyisocyanate (component B) to obtain an isocyanate reactive hydrogen prepolymer, which is then capped by reaction with an isocyanatofunctional alkoxysilane (component C).

6.

 Method according to claim 5, characterized in that for the synthesis of the prepolymer with isocyanate-reactive hydrogen a polyisocyanate defect is used in a ratio of NCO to Y1-H of 1.0 to 1.3 to 1.0 to 3.0 .

7.

 Method according to claim 5, characterized in that for the synthesis of the prepolymer with

Isocyanate-reactive hydrogen uses a polyisocyanate defect in an NCO to Y1-H ratio of 1.0 to 1.5 to 1.0 to 2.0. Method according to claim 5, characterized in that the reaction of the prepolymer with isocyanate-reactive hydrogen is carried out with an isocyanatofunctional alkoxysilane compound with a ratio of NCO to Y1-H of 0.8 to 1.0 to 1, 5 to 1.0. Use of the modified polymers with alkoxysilane groups according to claims 1 to 4 in adhesives, coatings and foams. 10. Adhesive and coating preparations containing from 10% by weight to 100% by weight of a polymer modified with alkoxysilane groups according to one of claims 1 to 4 or of a mixture of two or more such polymers modified with alkoxysilane groups, 15 from 0% by weight to 30% by weight of a plasticizer or a mixture of two or more plasticizers, from 0% by weight to 30% by weight of a solvent or a mixture of two or more solvents, from 0% by weight at 5% by weight of a moisture stabilizer or a mixture of two or more moisture stabilizers, from 0% by weight to 5% by weight of a UV stabilizer or a mixture of two or more stabilizers 20 vs. UV, from 0% by weight to 5% by weight of a catalyst or a mixture of two or more catalysts from 0% by weight to 80% by weight of a filler or a mixture of two or more fillers, adding the percentages of the components 100% by weight.